Linked Life Data

17715972

Source:http://linkedlifedata.com/resource/pubmed/id/17715972

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2007-9-7
pubmed:abstractText
Four new classes of organic solvent soluble ethynylpentacene derivatives (2,9-, 2,10-, 2,6,9,13-, 2,6,10,13-) have been prepared by complementary, versatile, double Diels-Alder strategies. Functional groups on the A, C, and E rings can be manipulated to increase the solubility, modulate the electronics, and alter the solid-state packing. Cycloaddition reactions with diene 2 and 1,4,5,8-anthradiquinone (3) or ortho-quinodimethane 19 with 1-butyl-3-methylimidazolim iodide (18) as the iodide source (a significant improvement over NaI) and benzoquinone (20) followed by in situ aromatization afforded the quinones 4, 5, 21, and 22, respectively. For the 2,9- and 2,10- families, a one-pot desilylation/triflation was developed. Palladium(0) coupling and reductive aromatization afforded 2,9-di(triisopropylsilylethynyl)pentacene (10) and 2,10-di(triisopropylsilylethynyl)pentacene (11), respectively. Photodimerization of these pentacenes afforded the air-stable [4 + 4] cycloaddition pentacene precursors (tetrakisnaphthotricyclo[4.2.2.22,5]dodecanes, 12-15). Thermal cycloreversion of the dimers ( approximately 13 J/g, approximately 4 kcal/mol) produces the parent pentacenes (10 or 11). The tetrasubstituted family utilized a parallel route with extra versatility as the timing of the Grignard and palladium(0) coupling step may be varied depending upon the functional group combinations desired. The subsequent reactions provided the tetraethynylpentacenes 28-30, 33-35 (para-isomers), and 38 (meta-isomer). X-ray crystallography analysis of 28, 29, and 33 revealed various pi-pi stacked packing motifs that differ from the unfavorable herringbone pattern of pentacene.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3263
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7229-36
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Double diels-alder strategies to soluble 2,9- and 2,9,6,13-tetraethynylpentacenes, photolytic [4 + 4] cycloadditions, and pentacene crystal packing.
pubmed:affiliation
Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't